pop@cs.umass.edu (02/19/91)
Concrete Syntax, off-side, Typography. The benefits of uncluttered indentation can be obtained far more cleanly by relegating parsers to where they belong - the past. What is needed is a way of allowing users to create an abstract syntax as a result of interacting with a workstation. This permits one to exploit the resources of mathematical typography as a tool for communicating with one's computer. OK - I overstated the case against parsing. It is desirable to be able to use parsers to interpret sequences of key-strokes during interactions. One of the capabilities that is most useful for this purpose is that of creating a smallest legal completion of a sequence of key-strokes, so that a meaningful display can always be maintained. The only system that does this to my knowledge is Theorist on the Macintosh (in another domain). Going back to indentation -- initial experiments with a Scheme presenter implemented in Pantechnicon indicate that it is reasonable to create indented structures with a template summoned up from the "soft keyboard" rather than by keying in the conditionals, function definitions etc.. Robin Popplestone.